土壤干旱对葡萄果实中黄烷醇类多酚时空积累及隐色花色素还原酶活性、组织定位的影响

【目的】葡萄果实发育过程中，土壤干旱对黄烷醇类多酚时空积累及其合成关键酶隐色花色素还原酶（leucoanthocyanidin reductase, LAR）活性和组织定位的影响。【方法】以5年生赤霞珠葡萄为试材，采用避雨棚和断根沟措施模拟土壤干旱，跟踪果实发育进程，采用分光光度计法、免疫组织定位等方法，就黄烷醇类多酚的时空积累及其合成关键酶LAR活性和组织定位进行研究。【结果】土壤干旱明显抑制葡萄果实生长，促进果实总酚积累，特别是在幼果期，土壤干旱明显促进葡萄果实总酚积累。土壤干旱未改变黄烷醇类多酚和总黄烷-3-醇的时空积累模式，但对其积累具有一定的诱导作用，且这一诱导作用具有明显的器官和发育阶段依赖性。土壤干旱明显诱导幼果期葡萄果皮和果肉中LAR酶活性增强，对LAR1、LAR2分布无明显作用，但诱导其积累，特别是在果肉维管束中，土壤干旱明显诱导LAR1、LAR2蛋白积累。【结论】土壤干旱诱导果实中LAR1、LAR2蛋白积累，进而导致LAR酶活性增强，最终表现为促进相应发育阶段、部位黄烷醇类多酚积累。

Spatial and Temporal Accumulation of Flavanols,Activity and Tissue Localization of Leucoanthocyanidin Reductase Induced by Soil Drought in Developing Grape Berries

【Objective】The effects of soil drought on the spatial and temporal accumulation of flavanols, enzyme activity and tissue localization of its biosynthetic key enzyme, leucoanthocyanidin reductase (LAR), during the grape berry development were studied.【Method】The 5-year old grapevine (Vitis vinifera L. cv. Cabernet Sauvignon) was used as materials, and the grapevine was subjected to soil drought stress simulated by controlling irrigation through the rain-preventing shelter and root-cutting groove during grape berry development. The spatial and temporal accumulation of flavanols and the enzyme activity of LAR in different parts of the grape berry were analyzed by spectrophotometer method, and the tissue localization of LAR was detected by the immunohistochemical localization. 【Result】 Results indicated that the growth of grape berry was significantly inhibited by soil drought during its development, and an obvious accumulation of total phenol in berry was induced by soil drought, especially in the young berry period. The accumulation pattern of flavanols and total flavan-3-ols in skin and flesh during grape berry development were not changed by soil drought, whereas an obvious accumulation of flavanols and total flavan-3-ols induced by soil drought was observed, and this effect was organ- and development-dependent. The LAR enzyme activity in skin and flesh was induced by soil drought, especially in the young berry period. There were no obvious changes of tissue localization of LAR1 and LAR2 in the skin and flesh under soil drought, but an increasing signal was detected, especially in the vascular bundle.【Conclusion】All the results of this study suggested that soil drought could induce the accumulation of LAR1 and LAR2 proteins in different parts of berry at different development stages, resulted in the increase of LAR enzyme activity in corresponding part and developing stage, and induced the accumulation of flavanols and total flavan-3-ols during grape berry development.